Absorbent products, such as diapers, having absorbent cores with various shapes have been known for some time. For example, the T-shaped absorbent core (U.S. Pat. No. 3,768,479) was introduced during the seventies. The T-shaped absorbent core provided an absorbent product with an absorbent structure having good fluid-storing properties, as well as it gave a good and stable fit to the wearer.
By U.S. Pat. No. 4,643,726 is an hour-glass shaped absorbent structure disclosed, which through its shape may absorb and store fluid to a greater extent than an absorbent core not being as large in size.
As mentioned, some advantages with a T-shaped and hour-glass shaped absorbent core is that the shape provides a good stability in the front part of the absorbent product. Moreover, the shape (or hour-glass shape) facilitates the absorbent structure to be correctly positioned in the longitudinal direction of the absorbent product, as it has a pre-disposed placement, due to the fitting of its shape between the legs of the wearer and the absorbent product. Further, the absorbent material of the “ears” and the front edge part of the core, not being in close proximity with the fluid waste source, i.e. urine, are used for storing fluid.
The absorbent cores are produced in a mat forming process, which usually is divided in two types: continuous and discontinuous mat forming.
In discontinuous mat forming each core is formed in a form having any desired shape. This process is advantageous due to its high flexibility with regard to the shape and surface of the core. Nevertheless, during manufacturing of an absorbent core having a T-shaped form, it has been shown that it is difficult to achieve a good absorption capacity in the “ears”, as the “ears” tend to become thinner than the rest of the absorbent core. This is a result of the mat forming process, and is especially significant at high production rates, or by manufacturing of thin layers. Thus, an absorbent product manufactured by this process has a sub-optimal fluid storing capacity.
As an alternative, continuous mat forming may be used, whereby the absorption cores are cut into discrete pieces after the formation process, which pieces are placed in the absorbent product. During continuous mat forming, it is optimal to keep the longitudinal core edges straight and parallel, as one otherwise end up with the problems described above for the discontinuous mat forming. As a result of this, the products from continuous mat forming are normally absorbent products comprising cores with a rectangular surface shape. This leads to a worse fit, and frequently also to an insufficient absorption capacity in the front part of the absorbent product.
Therefore, it is an object of the invention to avoid the drawbacks of the prior art and provide an absorbent product having an enhanced fluid storing capacity in the front part of the absorbent core.
Furthermore, it is an object of the invention to provide an absorbent product which provides a good fit and stability to the wearer, and which can be produced at a high production rate.